The present invention relates in general to sausages and, more particularly, to dry and semi-dry sausages and their preparation.
Dry and semi-dry sausages are generally classified as those sausages which have a relatively hard or chewy texture and have been fermented by allowing growth of selected bacteria during processing. The fermentation causes an accumulation of lactic acid and other byproducts which impart a tangy flavor to the sausage. Pepperoni, genoa, and hard salami are examples of popular dry sausages.
Production of most sausages is a very time-consuming process. In a typical process for preparing dry sausage, raw materials such as boneless chucks, beef trimmings, and regular lean pork are chopped and/or ground and then mixed with curing salts, seasonings and a starter culture of lactic acid producing bacteria. The mixture is stuffed into casings and the product is placed in fermentation rooms under controlled conditions to allow growth of the lactic acid producing bacteria. The bacteria causes fermentation of carbohydrates to produce the lactic acid which gives the sausage its characteristic flavor. The lactic acid also serves to lower the pH of the meat proteins toward their isoelectric point. This is particularly desirable because the meat proteins are less able to bind moisture as they approach their isoelectric point, thereby facilitating subsequent drying of the sausage.
Once the dry sausage is released from the fermentation room, it is typically placed in a drying room at temperatures in the range of 50.degree. F. to 75.degree. F. and relative humidities of 55 to 85% until the desired ratio of moisture to protein is achieved. In many instances, water in amounts up to 30 to 40% of the initial weight of the sausage must be removed over a period of several weeks or longer before the predetermined moisture to protein ratio is reached. Although more rapid drying such as by using higher temperatures would be desirable in order to reduce the processing time, the drying process must be conducted in a uniform and gradual manner in order to ensure a quality product. Rapid drying can cause hardening of the sausage casing which, in turn, can retard removal of moisture from the interior of the sausage.
Subjecting the sausage to high temperatures during drying or other processing steps may also adversely affect the suitability of the finished product for certain applications. For example, pepperoni slices used as pizza toppings should not cup or curl at the edges during cooking of the pizza because of the tendency for liquid to pool in the cupped slices and the likelihood that the edges will burn or dry out. Use of high temperatures during processing of the pepperoni is one factor which has been determined to contribute to cupping of the pepperoni slices.
In addition to the extended time periods required to properly dry sausages, governmental regulations require that dry and semi-dry sausage which are not cooked during processing be heat treated by holding the sausage for predetermined time periods at preselected temperatures. These times and temperatures are selected to ensure destruction of microorganisms such as trichinae which may be present in the meat and can lead to serious illness or death in humans. The time period required for drying is shortened by the use of higher temperatures and can be instantaneous when the product's internal temperature reaches approximately 145.degree. F. The use of these high temperatures during processing, however, can be detrimental to the performance of the final product when used for certain purposes such as pizza toppings. As a result, a need has developed for a sausage which can be processed at elevated temperatures without adversely affecting the performance of the resulting product.